Dual-mechanism Model Research Articles

On the cross-linguistic validity of a dual-mechanism model

Recent studies of Italian past definite and past participle forms show that human performance with regular and irregular inflections is not dissociated as Clahsen's model would predict. Some performance profiles, accounted for by dual-mechanism models in terms of an underlying symbol-manipulating combinatorial procedure, are generated in Italian by the higher learnability and generalizability of phonologically regular morphological processes.

And what about the Chinese?

We discuss other recent studies on the acquisition of the German plural that do not support the dual-mechanism model. The attested overgeneralizations are not by default only, nor completely random, but predictable from subregularities based on the grammatical gender and the phonology of the noun. In addition, the dual-mechanism model creates a number of problems for acquisition (theory) rather than solving existing ones.

The dual nature of the language faculty

The following discussion aims to illuminate further the way in which morphologically complex words are represented in the mental lexicon. It is argued that the dual-mechanism model can accommodate the linguistic and psycholinguistic evidence currently available, not only on German inflection (as pointed out in the target article) but also on other languages (as presented in several commentaries). Associative single-mechanism models of inflection, on the other hand, provide only partial accounts.

Neurolinguistic Evidence for Rule-Based Nominal Suffixation

This article presents a new set of experimental data from brain-damaged aphasic patients as well as from normals on the processing of two nominal suffixes in Japanese, i.e. -sa and -mi. Their difference with respect to productivity, as confirmed by the experiment on normal adults, provides evidence for the existence of a productive rule-like process in derivational morphology and supports the validity of the dual-mechanism model by integrating derivational morphology in its scope. The experiment on aphasic patients revealed a dissociation, which demonstrates that the two suffixation processes involve two different neurological mechanisms, and provides crucial evidence for the claim that the difference in the productivity of these two suffixes is of a qualitative nature and not a matter of degree.

The power of cross-linguistic analysis: A key tool for developing explanatory models of human language

Clahsen's compelling evidence for the dual-mechanism model of the lexicon derives in part from the use of cross-linguistic data in psycholinguistic research. This approach reflects a growing (and positive) trend toward incorporating data from several languages when analyzing and modeling human language behavior. This perspective should be expanded to include data from typologically distinct languages to develop more explanatory models of language.

Study of sorption in poly(vinyl alcohol) using the positron annihilationtechnique

The vacancy states of fresh and annealed poly(vinyl alcohol) polymers sorbing CO2 gas at various pressures have been investigated by the positron annihilation lifetime (PAL) technique. The change of the bulk volume and the amount of sorbed CO2 gas were measured simultaneously to compare the free volume fraction with the size of the ortho-positronium holes. The PAL data indicate that the size of the ortho-positronium hole increases with the progress of the sorption while the sorption and the bulk volume data show that the free volume fraction becomes constant. Also, it supports the existence of local plasticization and the improvement of the dual mechanism model of sorption of gas.

Acquiring Regular and Irregular Inflection in a Language with Verb Classes

The dual mechanism model claims that only rule-generated inflections are productive; that is, can be applied to words borrowed from other languages or derived from other grammatical categories (e.g. verbs derived from nouns or adjectives). Productivity, high generalisability and insensitivity to type or token frequency effects are intertwined properties of rule-generated inflections across languages (Pinker, 1991). We tested this cross-linguistic prediction in two experiments investigating Italian children's spontaneous performance with the past definite (Experiment 1) and their elicited performance with the past definite and the past participle (Experiment 2). Our findings show that performance profiles with productive and unproductive inflections cannot be “categorically distinguished”. The phonologically transparent morphological patterns exhibited by an unproductive verb class are high in generalisability when children make errors with root change verbs. The morphological patterns exhibited by a semi-productive class, which in Italian is consistently used with verbs derived from adjectives, are more correctly applied when forms are high in token frequency.

Irregular retention properties of 21-aminosteroid antioxidants in octylsilane bonded-phase high-performance liquid chromatography

The retention characteristics of two novel 21-aminosteroid antioxidants, 21-[ 4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl]-16α-methylpregna-1,4,9(11)-triene-3,20-dione dimethanesulfonate (I) and 21-[4-(2,5-di-N-diethylamine-2-pyridinyl)-1-piperazinyl]-16α-methylpregna-1,4,9(11)-triene-3,20-dione hydrochloride (II), in octylsilane bonded-phase high-performance liquid chromatography were examined in detail. Both I and II exhibited irregular retention behaviour which could be explained by the dual retention mechanism model proposed by A. Nahum and Cs. Horváth [J. Chromatogr., 203 (1981) 53]. Unless an amine modifier was added to competitively inhibit association with exposed silanol binding sites, the retention of both compounds in a 70% acetonitrile mobile phase was primarily due to silanophilic interactions. Addition of amine modifiers, lowering the pH, and increasing the sodium ion concentration of the mobile phase all decreased retention times, and modifiers capable of hydrogen bonding diminished peak tailing.

Carbon dioxide sorption and transport in polycarbonate

AbstractThe solubility, permeability, and diffusion time lag for carbon dioxide in polycarbonate are reported at 35°C for pressures ranging from 1 atm to 23 atm. The solubility data are very well described by the dual sorption mechanism model, Henry's law plus Langmuir adsorption, proposed for glassy polymers. Both the permeability and time lag decrease with increased CO2 pressure. These observations are not consistent with the proposal that CO2 sorbed by the Langmuir contribution is totally immobilized; however, all of the results are entirely consistent with an extension of this proposal which considers partial immobilization. The data have been quantitatively analyzed in terms of this partial immobilization model, and the results suggest for polycarbonate at 35°C that the CC2 sorbed by the Langmuir portion of the isotherm behaves as if it has only about 10% of the mobility of the gas sorbed by the Henry's law part of the isotherm. The results have also been interpreted in terms of a concentration‐dependent diffusion coefficient which is shown to be mathematically equivalent to the partial immobilization model. The latter model was also formulated in thermodynamic terms, whereby fugacity was used rather than pressure, and diffusion coefficients were defined in terms of chemical potential gradients rather than concentration, but the consequences of these changes proved to be minor and no better. The significance of these observations and their interpretation is discussed.

The kinetics of the brass-catalysed dehydrogenation of sec-butyl alcohol

The dehydrogenation of sec-butyl alcohol over a brass catalyst has been investigated in a stirred vessel reactor over the temperature range of 572 to 842°F at atmospheric pressure. The temperature range of this study extends the range of previous investigations which suggested that a dual mechanism model best characterizes the dehydrogenation from 550 to 700°F at 1 atm. It was found in the present study that a dual mechanism does appear to operate within this temperature range, and moreover that a second transition takes place at about 800°F to what is most probably the original low-temperature mechanism. Several advantages of the stirred vessel reactor are discussed.